System and method for realtime LED viewing angle correction

Abstract

A video display device includes LED pixels, a memory, and a processor. The processor receives video data that includes video pixels that correspond to the LED pixels. For at least some of the video pixels, the processor calculates a viewing angle for the LED pixel based on (i) a 3D location and optical axis vector for the LED pixel and (ii) a 3D location of a viewer of the LED pixel. The processor calculates a gain factor for the LED pixel based on the viewing angle and a relationship between pixel intensity and pixel viewing angle for the LED pixel. The processor calculates a compensated brightness for the LED pixel based on the gain factor and a brightness of the video pixel. The processor causes the LED pixel to emit light having the compensated brightness.

What is claimed is: 
     
       1. A video display device comprising:
 a plurality of light emitting diode (LED) pixels; 
 a memory storing instructions; and 
 a processor coupled to the plurality of LED pixels and the memory and configured to execute the instructions stored in the memory to:
 receive a frame of video data comprising a plurality of video pixels corresponding to the plurality of LED pixels; and 
 for at least some video pixels in the frame corresponding to LED pixels in the plurality of LED pixels:
 calculate a viewing angle for the LED pixel (θ horizontal , θ vertical ) based on (i) a three-dimensional (3D) location of the LED pixel (pixel x , pixel y , pixel z ) and (ii) a 3D location of a viewer of the LED pixel (viewer x , viewer y , viewer z ), where θ horizontal  is calculated from the values pixel x , pixel z , viewer x , and viewer z  and θ vertical  is calculated from the values pixel y , pixel z , viewer y , and viewer z ; 
 calculate a gain factor for the LED pixel based on the viewing angle (θ horizontal , θ vertical ) and a pixel gain table comprising information relating to a relationship between pixel intensity and pixel viewing angle for the LED pixel; 
 calculate a compensated brightness for the LED pixel based on the gain factor and a brightness of the video pixel; and 
 cause the LED pixel to emit light having the compensated brightness. 
 
 
 
     
     
       2. The video display device of  claim 1 , wherein each LED pixel of the plurality of LED pixels emit light in a plurality of colors, the gain factor for the LED pixel comprises an individual gain factor for each color of the plurality of colors, and the compensated brightness for the LED pixel comprises an individual brightness for each of the plurality of colors. 
     
     
       3. The video display device of  claim 1 , wherein the at least some video pixels in the frame comprise a subset of the video pixels in the frame, and the processor is configured to execute the instructions stored in the memory to:
 store viewing angles for the LED pixels that correspond to the video pixels in the subset; and 
 interpolate between two or more of the stored viewing angles to calculate the viewing angles for the LED pixels that correspond to the video pixels not in the subset. 
 
     
     
       4. The video display device of  claim 1 , wherein the at least some video pixels in the frame comprise a subset of the video pixels in the frame, and the processor is configured to execute the instructions stored in the memory to:
 store gain factors for the LED pixels that correspond to the video pixels in the subset; and 
 interpolate between two or more of the stored gain factors to calculate the gain factors for the LED pixels not in the subset. 
 
     
     
       5. The video display device of  claim 1 , wherein:
 the pixel gain table comprises a lookup table including a pixel gain factor for each of a plurality of viewing angles; and 
 the processor is configured to execute the instructions stored in the memory to interpolate between pixel gain factors for two or more of the plurality of viewing angles in the pixel gain table to calculate the gain factor for the LED pixel. 
 
     
     
       6. The video display device of  claim 1 , wherein the processor is configured to execute the instructions stored in the memory to calculate the viewer position information based on a plurality of 3D locations of a corresponding plurality of viewers of the plurality of LED pixels. 
     
     
       7. The video display device of  claim 1 , wherein the processor is configured to execute the instructions stored in the memory to calculate the gain factor for the LED pixel further based on a compensation strength control parameter. 
     
     
       8. A video processing device, comprising:
 a memory storing instructions; and 
 a processor coupled to the memory and configured to execute the instructions stored in the memory to:
 generate a viewing angle map comprising individual viewing angles (θ horizontal , θ vertical ) for each of a plurality of light emitting diode (LED) pixels of a video display device, the individual viewing angles based on (i) individual three-dimensional (3D) locations (pixel x , pixel y , pixel z ) of each LED pixel of the plurality of LED pixels and (ii) a 3D location of a viewer of the LED pixel (viewer x , viewer y , viewer z ), where θ horizontal  for the individual LED pixel is calculated from the values pixel x , pixel z , viewer x , and viewer z  and θ vertical  for the individual LED pixel is calculated from the values pixel y , pixel z , viewer y , and viewer z ; 
 generate a pixel gain map comprising individual gain factors for the plurality of LED pixels based on the individual viewing angles (θ horizontal , θ vertical ) of the viewing angle map and a pixel gain table comprising information relating to a relationship between pixel intensity and pixel viewing angle for the LED pixels; 
 generate frames of compensated video data by calculating compensated video pixel brightness in received frames of a video signal based on the pixel gain map; and 
 transmit the frames of compensated video data to the video display device, the frames of compensated video data configured to cause the LED pixels to emit light having the compensated video pixel brightness of corresponding video pixels. 
 
 
     
     
       9. The video processing device of  claim 8 , wherein the LED pixels emit light in a plurality of colors and the pixel gain map comprises individual gain factors for each of the plurality of colors emitted by the LED pixels. 
     
     
       10. The video processing device of  claim 8 , wherein the processor is configured to execute the instructions stored in the memory to calculate the viewer position information based on a plurality of 3D locations of a corresponding plurality of viewers of the video display device. 
     
     
       11. The video processing device of  claim 8 , wherein the processor is configured to execute the instructions stored in the memory to:
 generate the viewing angle map for a subset of the LED pixels; and 
 interpolate between the individual viewing angles for two or more of the LED pixels in the subset to calculate the individual viewing angles for the LED pixels not in the subset. 
 
     
     
       12. The video processing device of  claim 8 , wherein the processor is configured to execute the instructions stored in the memory to:
 generate the viewing angle map for a subset of the LED pixels; 
 generate the pixel gain map for the subset of the LED pixels; and 
 interpolate between the individual gain factors for two or more of the LED pixels in the pixel gain map to calculate the individual gain factors for the LED pixels not in the subset. 
 
     
     
       13. The video processing device of  claim 8 , wherein:
 the pixel gain table comprises a lookup table including a pixel gain factor for each of a plurality of viewing angles; and 
 the processor is configured to execute the instructions stored in the memory to interpolate between pixel gain factors for two or more of the individual viewing angles in the pixel gain table to calculate the gain factor for the LED pixel. 
 
     
     
       14. The video processing device of  claim 8 , wherein the processor is configured to execute the instructions stored in the memory to calculate the individual gain factor for the LED pixel further based on a compensation strength control parameter. 
     
     
       15. A video processing device, comprising:
 a memory storing instructions; and 
 a processor coupled to the memory and configured to execute the instructions stored in the memory to:
 generate a viewing angle map comprising individual viewing angles (θ horizontal , θ vertical ) for each of a plurality of light emitting diode (LED) pixels of a video display device, the viewing angle map based on (i) individual three-dimensional (3D) locations (pixel x , pixel y , pixel z ) of each LED pixel of the plurality of LED pixels and (ii) a 3D location of a viewer of the LED pixel (viewer x , viewer y , viewer z ), where θ horizontal  for the individual LED pixel is calculated from the values pixel x , pixel z , viewer x , and viewer z  and θ vertical  for the individual LED pixel is calculated from the values pixel y , pixel z , viewer y , and viewer z ; 
 generate a pixel gain map comprising individual gain factors for the LED pixels based on the viewing angle map and a pixel gain table comprising information relating to a relationship between pixel intensity and pixel viewing angle for the LED pixels; and 
 transmit the pixel gain map to a video display device, the pixel gain map configured to cause the video display device to compensate pixel brightness of received frames of a video signal based on the pixel gain map. 
 
 
     
     
       16. The video processing device of  claim 15 , wherein the LED pixels of the video display device emit light in a plurality of colors and the pixel gain map comprises individual gain factors for each of the plurality of colors emitted by the LED pixels. 
     
     
       17. The video processing device of  claim 15 , wherein the processor is configured to execute the instructions stored in the memory to:
 generate the viewing angle map for a subset of the LED pixels; and 
 interpolate between the individual viewing angles for two or more of the LED pixels in the subset to calculate the individual viewing angles for the LED pixels not in the subset. 
 
     
     
       18. The video processing device of  claim 15 , wherein the processor is configured to execute the instructions stored in the memory to:
 generate the viewing angle map for a subset of the LED pixels; 
 generate the pixel gain map for the subset of the LED pixels; and 
 interpolate between the individual gain factors for two or more of the LED pixels in the pixel gain map to calculate the individual gain factors for the LED pixels not in the subset. 
 
     
     
       19. The video processing device of  claim 15 , wherein:
 the pixel gain table comprises a lookup table including a pixel gain factor for each of a plurality of viewing angles; and 
 the processor is configured to execute the instructions stored in the memory to interpolate between pixel gain factors for two or more of the individual viewing angles in the pixel gain table to calculate the individual gain factor for the LED pixel. 
 
     
     
       20. The video processing device of  claim 15 , wherein the processor is configured to execute the instructions stored in the memory to calculate the individual gain factor for the LED pixel further based on a compensation strength control parameter.